Air Intake Restrictor with A-B test

[ConnClark]

Originally Posted by mwebb

the US EPA and IATn have conducted pretty thorough testing which shows that up to about 50% restriction of the air filter has about zero effect on fuel economy On Fuel Injected systems , it does reduce maximum flow and so will reduce maximum power output -

these tests were in response to the many false claims of various vendors including but not limited to K & N that replacing air filters could somehow magically improve fuel economy

it does not
as demonstrated by the test results in at least 3 separate sets of testing

Those tests were on new throttle body or fuel injected gasoline powered cars. A clean air filter does improve mileage on diesels and cars with a carburetor.

[Arragonis]

Originally Posted by Fr3AkAzOiD

...

Not sure if I have a MAP or MAF. If it's important I can look it up.

...

Just wondered about a WAI to do the same, less dense air = less fuel, or so the theory goes at least. As unproven as air tabs, but maybe slightly more potential.

[tru]

by reducing the size of the intake, do you not reduce horsepower?

reducing horsepower would be more beneficial at idle i would think. if you could test to see how your gph changes when sitting at a stop light with your restricted intake. this may not be worth anything at speed but may be beneficial at idle

[mwebb]

the new diesel common rail systems use intake restriction to improve EGR flow at cruise , so partially restricted air filters will have little to no detrimental effect on FE .

there are so few cars with carbs remaining that it does not matter ,ALL cars with carbs get poor FE compared to systems with fuel injection and engine management .

Originally Posted by ConnClark

Those tests were on new throttle body or fuel injected gasoline powered cars. A clean air filter does improve mileage on diesels and cars with a carburetor.

[mwebb]

Originally Posted by tru

by reducing the size of the intake, do you not reduce horsepower?

reducing horsepower would be more beneficial at idle i would think. if you could test to see how your gph changes when sitting at a stop light with your restricted intake. this may not be worth anything at speed but may be beneficial at idle

restricting intake tube diameter MAY reduce maximum available power output , but it also may be an improvement to FE and BSFE at cruise and lighter loads as the velocity of the intake charge will be increased with smaller diameter intake runners , which will improve volumeteric efficiency - your results will vary depending on how it is done -

depending on what is restricted , and how it is restricted , FE can be improved or UN changed , maximum power output , torque and horse power will be always be reduced , a restriction plate in the air filter will never improve FE , but up to 50% restriction , will not degrade FE either

[Arragonis]

Would you need something like these to aid the higher intake speed ?



EDIT - or of course a single one.

[ConnClark]

Originally Posted by mwebb

the new diesel common rail systems use intake restriction to improve EGR flow at cruise , so partially restricted air filters will have little to no detrimental effect on FE .

To the contrary, what auto makers must do to meet EPA mandates for emissions is very detrimental to fuel economy. To claim otherwise is a very poor argument.

there are so few cars with carbs remaining that it does not matter ,ALL cars with carbs get poor FE compared to systems with fuel injection and engine management .

There Are lots of cars with carbs still. Go to any car parts store and they have brand new carbs for sale. It it is irrelevant that cars with carbs get worse fuel economy than cars with fuel injection. What is relevant is cars with carbs exist and get better fuel economy with a clean airfilter.

[suspectnumber961]

Someone has claimed that with a Ford Focus...removing the tube going to the front of the hood (fresh air) and allowing air to directly go into the bottom of the filter box resulted in increased mpg. Less restriction and warmer air.

I'll eventually try this...but won't like the noise when it's punched....the throttle that is.

[99LeCouch]

Originally Posted by suspectnumber961

Someone has claimed that with a Ford Focus...removing the tube going to the front of the hood (fresh air) and allowing air to directly go into the bottom of the filter box resulted in increased mpg. Less restriction and warmer air.

I'll eventually try this...but won't like the noise when it's punched....the throttle that is.

It's true on my Cruze too. The airbox opens right to the engine bay without all the fresh air crap in the way. I can also hear the turbo spool with the excessive intake stuff removed, so it's an auditory reminder to get out of boost when possible.

[mwebb]

Originally Posted by ConnClark

To the contrary, what auto makers must do to meet EPA mandates for emissions is very detrimental to fuel economy. To claim otherwise is a very poor argument.

"the new diesel common rail systems use intake restriction to improve EGR flow at cruise , so partially restricted air filters will have little to no detrimental effect on FE ."

whatever the above reply is meant to say ...
on a common rail diesel system at cruise , a restricted air filter still will have very little to no detrimental effect on FE

and
generally speaking
clean emissions do not have a detrimental effect on fuel economy as overall efficiency improves as overall emissions go down .

consider a carburated system from the 70s and a 2012 any car from now ....
same mass ,
FE is better by a huge percentage and emissions are greatly reduced on the
current systems compared to the 70s cars

except for
particulate filter regeneration on the new common rail diesel systems , on the cars i work with , FE was better on the older systems that did not use
particulate filter regeneration and did have engine management systems

those are the facts